1. Field of the Invention
The present invention relates to a corrosion-free electrical connector structure and more particularly to an electrical connector structure which is positioned in a fuel tank and prevents corrosion of electrodes for power supply to a fuel pump.
2. Related Art
In-tank type fuel pump is known in the art as disclosed in JP-A-3-23359. The fuel pump of this kind is placed vertically or upright in a fuel within a fuel tank or in a sub-tank placed in the fuel tank. The pump has at its uppermost portion an electrical connector of a tubular shape for receiving electric power supply for an electric motor. As shown in FIG. 5A, a female connector 103 connected to a power supply source is inserted and fitted into a tubular wall 101 of a male connector of the pump and an engagement nail 105 of female connector 103 engages with a lock window or opening 107 of wall 101. It is also known to form lock window 107 in a slit shape extending to the lowermost portion as shown in FIG. 5B.
In the case of the fuel tank used for an automotive vehicle, fuel sometimes contains small amount of water. Since the specific gravity of the water is higher than that of the fuel, water may be accumulated gradually within the tubular wall of the connector during repetition of increase and decrease of fuel liquid level in the fuel tank. This will result in corrosion of connector electrodes.
In addition, accumulation of degraded fuel in the tubular wall of the connector will bring about corrosion of the connector electrodes.
The above accumulation of water is caused more often in the case of the connector, which has a closed bottom and a cup-shaped inner space as shown in FIG. 5A. Further, even in the case of the connector with slit 107 extending from the top to the bottom as shown in FIG. 5B, water in the fuel tends to stick to the angled corner at the inside of the connector due to surface tension. As a result, only fuel can be discharged through slit 107 and water is accumulated, thus causing corrosion of the electrodes.